Lecture 8 2/11/25 Flashcards
What are the components of every dermatitis?
crusts and scale
What is the presentation of genetic cornification disorders?
-generalized distribution
-diagnosed in young dogs
What are the definitions of crust, scale, and visible scale?
-crust = serum + cells
-scale = keratin
-visible scale = seborrhea
What are the characteristics of normal keratinization?
-keratinocytes are a slowly renewing cell pop.
-migration from basal cell layer to stratum corneum takes around 22 days
-normal desquamation is not visible
What are the characteristics of seborrhea?
-formation of visible scale +/- excess grease
-increased epidermal turnover
-abnormal cornification
-abnormal glandular function
-can be primary or secondary
What are the possible clinical presentations of seborrhea?
-focal or generalized
-mild or severe
-dry, waxy, or greasy
What are the secondary changes seen with seborrhea?
-alopecia
-inflammation
-pruritus
-pyoderma
-lichenification
-hyperpigmentation
-odor
-malassezia colonization
What are the secondary causes of seborrhea/keratinization disorders?
-allergy/other pruritic dermatoses
-external causes such as scabies, lice, and demodicosis
-pyoderma (most common cause)
-endocrinopathies
-pemphigus foliaceus
-epitheliotropic lymphoma
-environmental influences
-nutritional problems
What are the characteristics of primary keratinization disorders?
-hereditary/genetic
-first appear in young animals
-major defect is increased cell renewal time
-often associated with secondary infection
-must rule out secondary causes when attempting to diagnose
What are the steps to diagnosing a primary keratinization disorder?
-rule out infections and secondary causes first
-biopsy; most important tool for diagnosis of primary conditions
Which breeds are affected by primary idiopathic seborrhea?
-cocker spaniels
-springer spaniels
-west highland white terriers
-basset hounds
-setters
-dobermans
-labrador retrievers
-shepherds
-dachshunds
What are the treatment options for primary idiopathic seborrhea?
-vitamin A or retinoids
-fatty acids for seborrhea sicca
-topical antiseborrheic therapy
-cyclosporine
-antibiotics for secondary infections
-malassezia treatment if needed
What is vitamin A-responsive dermatosis most likely to be?
primary seborrhea of cocker spaniels
What are the clinical signs of vitamin A-responsive dermatosis?
-comedones
-follicular fronding or casts
-primarily affects trunk
-follicular seborrhea
How is vitamin-A responsive dermatosis diagnosed?
-histopath. that shows follicular keratoses
-response to treatment
What are the characteristics of genetic zinc-responsive dermatosis?
-seen in huskies and malamutes, can occur in other breeds
-defective zinc absorption
What are the characteristics of zinc-responsive dermatosis in large breed puppies?
occurs with:
-nutritionally poor diet
-diets high in phytates
-diets high in calcium
What is a possible third type of zinc-responsive dermatosis?
dogs with concurrent illness/stress
What is the clinical presentation of zinc-responsive dermatosis?
-alopecia, scaling and crusting of the face, genitalia, and friction points
-foot-pad hyperkeratosis
-secondary infections
-lymphadenopathy
-possible pruritis
How is zinc-responsive dermatosis diagnosed?
biopsy that shows parakeratotic hyperkeratosis and tissue eosinophils
What is the treatment for zinc-responsive dermatosis?
-zinc supplementation
-diet change to one with animal-based protein
-discontinuation of diet supplements
-low dose prednisone if lack of response to zinc alone
What are the characteristics of epidermal dysplasia of west highland white terriers?
-genetic keratinization abnormality
-occurs in dogs less than 1 year of age
What are the clinical signs of epidermal dysplasia of WHWT?
-extreme pruritus
-severe seborrhea
-secondary malassezia and/or pyoderma
-secondary otitis
What are the treatment options for epidermal dysplasia of WHWT?
-treat secondary infections
-try cyclosporine and steroids
-possibly apoquel or cytopoint
-not very rewarding
What are the characteristics of ichthyosis?
-rare hereditary defects of keratinization
-presents with excessive hyperkeratosis
-some animals abnormal at birth; others shortly after
-biopsy is usually diagnostic
What are the characteristics of ichthyosis of golden retrievers?
-milder form
-may not be clinical at birth
-large black to gray scales
-autosomal recessive disorder
What are the characteristics of sebaceous adenitis?
-inflammation and destruction of sebaceous glands
-genetic predisposition
-though to have immune-mediated component, but cause is unknown
Which breeds are predisposed to sebaceous adenitis?
-standard poodle
-vizsla
-samoyed
-akita
What is the clinical presentation of sebaceous adenitis in long-haired dogs?
-young adult dogs
-patchy alopecia and scale
-follicular casts
-non-pruritic
-secondary infections
What is the clinical presentation of sebaceous adenitis in short-haired dogs?
-moth-eaten alopecia
-non-pruritic
-secondary infections; less common than long-haired
-nodular lesions described
How is sebaceous adenitis diagnosed?
-histopath. showing inflammation directed at sebaceous glands
OR
-histopath showing no sebaceous glands and hyperkeratosis
What are the treatment options for sebaceous adenitis?
oil replacement works best
-propylene glycol topically
-essential fatty acids
-vitamin A
-synthetic retinoids
-antibiotics
-glucocorticoids
-cyclosporine
-possibly tetracycline/niacinamide
What are the characteristics of idiopathic nasodigital hyperkeratosis?
-aging change in many dogs
-dry and flaky appearance
What are the characteristics of hereditary nasal parakeratosis of labradors?
-first seen in younger dogs
-fluid-filled small cysts along nasal planum
What are the characteristics of schnauzer comedone syndrome?
-follicular keratinization defect along dorsal midline
-often associated with folliculitis and/or furunculosis
-treatment includes shampoos, vitamin A, and antibiotics
What are the characteristics of ear margin “seborrhea”?
-primarily seen in dachshunds and uncropped boxers
-ischemic dermatosis
-want to look for tick-borne dz and rule out causes of vasculitis/vasculopathy
-bilateral scaling and alopecia along ear margins
-may progress to necrosis and scalloped edges
What are the treatment options for ear margin seborrhea?
-pentoxifylline
-doxycycline
-topical keratolytics
-topical and/or systemic steroids
What are the characteristics of primary keratinization disorders in cats?
-rare
-mainly seen in persians
-idiopathic seborrhea that presents as seborrhea oleosa
-generalized or face only
What are the treatments for primary keratinization disorders in cats?
-address secondary infections
-may see response to cyclosporine/tacrolimus
What are the characteristics of feline acne?
-reaction pattern or idiopathic
-comedones progress to furunculosis
How is feline acne diagnosed?
-scrape
-cytology
-possible culture
-possible biopsy
-rule out demodicosis
What are the treatment options for feline acne?
-topical benzoyl peroxide or ethyl lactate
-topical mupirocin
-systemic antibiotics as indicated
-topical retinoids
-change bowls from plastic to glass, ceramic, or steel
-hypoallergenic food trial
-flea control
What are the characteristics of tail gland hyperplasia/stud tail?
-seen in both sexes in dogs
-castration does not resolve condition
-may result from poor grooming when over-stressed
-symptomatic treatment
